Apparatus and method for locking a tire vulcanizing press

ABSTRACT

A tire press has an upper mold fixedly attached to a top plate. A bottom mold is fixedly attached to a bottom plate. The tire press has a plurality of guide posts adapted to maintain proper alignment of the upper mold and the lower mold as the tire press opens and closes. A plurality of lock rods, which are independent of the guide posts, are positioned about the tire press. Each of the lock rods has a first end and a second end. The lock rods may have an adjustment mechanism positioned on the first end of the lock rods to adjust the various mold heights. Locking means are a part of the tire press, which are adapted to selectively engage the second end of the lock rods. Further, each of the lock rods has cylinder mechanism operatively connected to the locking means. The cylinder mechanism is adapted to force the locking means to the surface of the lock rods. The cylinder mechanism is a hydraulic cylinder having the piston disposed within the chamber. The piston has a release side and a squeeze side, such that when fluid is introduced on the squeeze side, a substantially equal amount of tension is placed on the lock rods to lock the tire press. When fluid is introduced on the release side, the locking means can be removed from the lock rods and the tire press can be opened.

This application is a continuation application claiming priority from autility patent application filed on Aug. 16, 2002, having Ser. No.10/222,742. Inventorship remains the same.

I. BACKGROUND OF THE INVENTION

A. Field of Invention

This invention pertains to the art of methods and apparatuses forlocking a tire press.

More specifically, the present invention pertains to the art of methodsand apparatuses for locking a tire press wherein a cylinder mechanism isutilized to provide substantially equal tension in all locking rods suchthat the tolerances for the length of each of the lock rods is not ascritical as in known locking devices.

B. Description of the Related Art

It is known in the art for tire presses to have a locking mechanism sothat a tire mold is secure during a curing cycle. Current devicesutilize lock rods which must be substantially identical in length. Assuch, the lengths must be very precise and is very critical. Thedimension is very critical because when a tire press closes and locks,if any of the lock rods are slightly longer than another one, theshorter rod sees more forces and loads. This results in an uneven loaddistribution which results in uneven strains and stresses. This mayeventually cause tire defects because upper and lower tire molds may nolonger be parallel. Further, the lock rods need to be over designed totake into consideration the fact that some of the lock rods mayencounter more loads than others.

In other known designs, tension is place on the lock rods; however, thelock rods and the guide posts of the tire press are the same mechanism.In this case, guide posts that have a locking mechanism integratedtherein encounter increased maintenance. This is because guide postsshould only be used for guiding the upper and lower mold halves open andclosed during curing cycles. When actual forces are placed on guideposts through a locking mechanism, forces may cause deflection in theguide posts over time. As such, guide posts need routine maintenance.

The present invention provides methods and apparatuses for locking atire press, which has independent lock rods and guide posts, and doesnot require the lock rods to be exactly equal in length, and yet,provides equal tension and axial forces in all the lock rods when thetire press is closed and locked.

II. SUMMARY OF THE INVENTION

According to one aspect of the present invention, a new and improvedlocking mechanism for a tire press is provided. A tire press has anupper mold fixedly attached to a top plate. A bottom mold is fixedlyattached to a bottom plate. The tire press has a plurality of guideposts adapted to maintain proper alignment of the upper mold and thelower mold as the tire press opens and closes. A plurality of lock rods,which are independent of the guide posts, are positioned about the tirepress. Each of the lock rods has a first end and a second end. The lockrods may have an adjustment mechanism positioned on the first end of thelock rods to adjust for various mold heights. Locking means are a partof the tire press and are adapted to selectively engage the second endof the lock rods. Further, each of the lock rods has cylinder mechanismoperatively connected to the locking means. The cylinder mechanism isadapted to extend the locking means to the surface of the lock rods. Thecylinder mechanism may be a hydraulic cylinder having the pistondisposed within the chamber. The piston has a release side and a squeezeside, such that when fluid is introduced on the squeeze side, asubstantially equal amount of tension is placed on the lock rods to lockthe tire press. When fluid is introduced on the release side, thelocking means can be removed from the lock rods and the tire press canbe opened.

Another object of the present invention is to provide an apparatushaving a lock rod with first end, a second end, and a surface; lockingmeans operatively connected to the lock rod; and, cylinder mechanismoperatively connected to the locking means, wherein the cylindermechanism is adapted to extend the locking means to the surface of thelock rod, the cylinder mechanism also being adapted to place tension onthe lock rods.

Still yet, another object of the present invention is to provide a tirepress where the locking means is a split lock ring.

Another object of the present invention is to provide a tire presswherein the lock rod is moveable relative to the top plate.

Further, another object of the present invention is to provide a tirepress, wherein the lock rod is threaded on the first end.

Still yet, another object of the present invention is to provide a tirepress, wherein tension in each of the lock rods is substantially equal.

Further, another object of the present invention is to provide a methodfor locking the tire press comprising the steps of:

-   -   providing a tire press having an upper mold and a lower mold, a        lock rod having a first end and a second end, the lock rod        having a surface, locking means, and, cylinder mechanism        operatively connected to the locking means, wherein the cylinder        mechanism is adapted to extend the locking means to the surface        of the lock rod;    -   closing the tire press;    -   locking the locking means to said lock rod;    -   placing tension on the lock rod with the cylinder mechanism;        and, locking the tire press.

Still, another object of the present invention is to provide a methodfor locking the tire press wherein the step of placing tension on thelock rod with the cylinder mechanism further comprises the step ofinjecting a fluid on the squeeze side of the piston.

Still, another object of the present invention is to provide a methodfor unlocking the tire press further comprising the steps of:

-   -   injecting fluid on the release side of the piston;    -   removing fluid from the squeeze side of the piston;    -   releasing the locking means; and    -   unlocking the tire press.

It is yet another object of the present invention to provide an improvedloader/unloader system with the tire press.

It is yet another object of the present invention to provide a tirepress that is more compact in size such as to eliminate the need for apit in the factory floor and additional width.

Still other benefits and advantages of the invention will becomeapparent to those skilled in the art to which it pertains upon a readingand understanding of the following detailed specification.

III. BRIEF DESCRIPTION OF THE DRAWINGS

The invention may take physical form in certain parts and arrangement ofparts, a preferred embodiment of which will be described in detail inthis specification and illustrated in the accompanying drawings whichform a part hereof and wherein:

FIG. 1 is a perspective view of a hydraulic curing press.

FIG. 2 is a cross-sectional view of the top of a lock rod disposedwithin the top plate of the tire press in FIG. 1.

FIG. 3 is a cross-sectional view of the second end of a locking rodshowing the cylinder mechanism and the locking means.

FIG. 4 is a top, cross-sectional view of a lock ring.

FIG. 5 is a side elevational view of the loader, unloader and green tireholder of the tire press.

IV. DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to the drawings wherein the showings are for purposes ofillustrating a preferred embodiment of the invention only and not forpurposes of limiting the same, FIGS. 1-5 show the present invention.

With reference to FIGS. 1-4 a tire press 10 is shown. A tire press 10may take the form of two single cavity machines that work independently.The tire press comprises a top plate 12 having an upper mold 14 rigidlyaffixed thereto. A bottom mold 18 is fixedly attached to the bottomplate 16. The bottom mold 18 and upper mold 14 contact each other andmaintain alignment through a plurality of guide rods 20.

The tire press 10 further comprises a plurality of lock rods 22, whichpasses through the top plate 12. Each of the lock rods has a first end24, a second end 26, and a surface 32. The second end 26 may be notched.The purpose of the lock rods 22 is to maintain tight and even sealbetween the upper mold 14 and bottom mold 18 during a curing cycle. Itis important that the lock rods 22 be independent from the guide rods20. In order to achieve optimal sealing and closure between the upperand bottom molds 14, 18, only the lock rods 22 should be utilized. Ifguide rods 20 are utilized to perform a locking function in the tirepress 10, the guide rods 20 will experience unwanted deflection, whichcould ultimately result in imperfect sealing of the molds 14, 18 duringa curing cycle.

With reference to FIG. 2, the first end 24 of the lock rod 22 maycomprise an adjustment mechanism 28. Any adjustment mechanism may beutilized that is chosen with sound engineering judgment; however, asshown in the figures, the adjustment mechanism 28 shown is threads 30.The adjustment mechanism 28 has an adjusting screw sprocket 36, whichattaches to an adjusting nut 34. Because the lock rods 22 pass throughthe top plate 12, the lock rod 22 is moveable relative to the top plate12 through the adjustment mechanism 28 described herein. A top adjustingthrust washer 38 and a bottom adjusting thrust washer 40 are shown.These washers 38, 40 are adapted to take up any thrust and axial loadexperienced during the locking of the tire press 10. Further, anadjusting nut spacer 42 and adjusting nut retaining ring 44 aid theadjustment mechanism 28 and the lock rod 22. The lock rod 22 passesthrough a hole in the bottom plate 16. A top heat shield 46, middle heatshield 50 and bottom heat shield 52 are utilized to prevent excessiveheat from escaping the mold. Further, a lock rod anti-rotation bracket48 prevents rotation of the lock rods 22.

With reference to FIG. 2, the heat shields 46, 50 and 52 will now beexplained in further detail. The top heat shield 46 is attached to thetop plate 12. The middle heat shield 50 is attached to the lock rod 22,and the bottom heat shield is attached to the bottom plate 16. Because amiddle heat shield 50 is attached to each of the lock rods 22 at theproper dimension, this enables the middle heat shield 50 toautomatically adjust to the proper height to shield the mold. As such,heat shield adjustment is concurrent with lock rod adjustment.

With reference to FIG. 4, locking means 54 is shown. Locking means 54may take the form of a split lock ring 56. The split lock ring 56 maycomprise a first arm 58 and a second arm 60. First and second arms 58,60 define a hole 62 therebetween. The opening and closing of these lockrings 56 may be controlled by a pneumatic cylinder 64. Further, the lockring 56 may further comprise a proximity switch sensor 66 so that thefirst and second arms 58, 60 maintain the appropriate position duringthe opening and closing of the lock ring 56.

With reference to FIG. 3, cylinder mechanism 90 is shown in the squeezecondition (left side) and the release condition (right side). In thepresent invention, the cylinder mechanism may take the form of ahydraulic squeeze cylinder 92. The cylinder 92 comprises a chamber 94having a floating piston 96 disposed therein. The piston 96 has asqueeze side 98 and release side 100. As shown in FIG. 3, the lock ring56 is adapted to encircle the notched second end 26 of the lock rod 22.A fluid is introduced into the squeeze side 98 of the piston 96, whichresults in a downward axial force, which pushes down on the lock ring56, which then contacts and pushes down on the lock rod 22, resulting intension in the lock rod 22. In other words, the cylinder mechanism isadapted to move or force the locking means to the surface of said lockrod. The stroke of the piston 96 may be an inch or any other distancechosen with sound engineering judgment. Separate locking means 54 andcylinder mechanism 90 may be used for each of the lock rods 22. It isalso contemplated that the cylinder mechanism 90 may have a spring tobias the piston 96 upwards (not shown).

As previously stated, the length of lock rods in previous devices isvery critical because shorter lock rods will bear more stress and strainthan longer lock rods. This results in increased cost to provide forbigger and stronger lock rods, as well as increased maintenance. Becausethe self-adjusting stroke length of the piston 96 and the common supplyof pressure to the cylinder mechanism 90, equal force will be applied toeach lock rod regardless of the varying lengths of the individual lockrods 22. Any imperfections in the threads 30 of the adjustment mechanism28 and/or any imperfections in the lengths of the lock rods 20 areresolved through the tension produced by the hydraulic cylinder 92.

By means of the adjustment mechanism 28, and more specifically, throughthe multiple nuts 34, the nuts 34 are turned in unison by a connection,which may be a chain drive, which in turn elevates the lock rods 22 tothe desired height for a particular mold. This allows for a correct moldheight to be set as different molds are changed within the tire press10. This can be done automatically with proximity sensors (not shown).During a mold change, the lock rods 22 of the tire press 10 are in theirmost upright position. When the tire press 10 is closed on the molds,the lock rods 22 are driven down until it is sensed that they are in thelocking position. At such time, the proximity sensors will sense thelocking position and automatically stop the mold height adjustment.

When the hydraulic cylinder 92 is energized, it will push to theposition shown in the left side of FIG. 3 and put force on the lock rod22. The rod 22 is pulling on the upper mold 14 and into the lower mold18. The axial forces experienced by the lock rods 22 are very evenbecause the top plate 12 is being brought down by three points, whichwill level itself through hydraulic cylinders 92 which are all connectedtogether with the same hydraulic supply line. Hydraulic oil pressureenables this equalization and gives a very equal and parallel pull down.This results in a more even and parallel squeeze of the mold.

When the cylinder mechanism 90 pushes down on each of the lock rods 22,a centerline through the shaft of all three lock rods 22 will have equalpull down at the same time. The pressure is evenly distributed amongeach lock rod 22. Thus, an advantage is gained on equal distribution ofstresses and equal deflection on the bottom plate 16 and top plate 12.Further, while deflection is occurring with the lock rod 22, the guiderods 20 experience virtually zero axial forces since they areindependent of the lock rods 22.

In yet another embodiment of the invention, springs may be utilized toconform with guide tubes 82. When the hydraulic cylinders 92 pull thelock rods 22 downward, it is possible that deflection would reach theguide tubes 82. The springs would actually release the guide tubes 82 toallow its conformity with the axis of the guide rods 20. Morespecifically, a flange would lift so that the guide tube 82 wouldcontinue to experience little or no axial forces or bending forces.

Because the lock rods 22 are equally spaced and are utilized inconjunction with floating pistons 92, the balanced tension results in aperfect parallel plane between the top and bottom plates 12, 16. Each ofthe lock rods 22 experiences equal deflection, which is no more than0.005 inches. This is attributed to the lock rods 22 being equallyspaced about the perimeter of the molds 14, 18 and the thickness of thetop and bottom plates 12, 16, which have a height up to six inches. Thisconfiguration also results in a very flat, parallelism and concentricityof the molds 14, 18. Another advantage of this configuration is theelimination of irregularly shaped welded structural supports for the topplate 12 and/or bottom plate 16 to secure the top and bottom molds 14,18. Welds in the squeeze area and load path are eliminated.

Having just described the present invention, its operation will now bedescribed. A tire press 10 as previously described is provided. The tirepress 10 is closed by lowering the upper mold 14 to the bottom mold 18.The locking means 54 is locked to the second end 26 of lock rod 22. Morespecifically, the pneumatic cylinder 64 is actuated so that the firstand second arms 58, 60 of split lock ring 56 encircle the notched secondend 26 of the lock rod 22. Upon closure of the lock ring 56, the lockingmeans 54 is secured to the second end 26 of the lock rod 22. Next,fluid, such as a hydraulic fluid, is injected on the squeeze side 98 ofthe piston 96. The pressure created by the fluid forces the piston 96downward, thus pushing down on the lock ring 56. The lock ring 56 movesdownward until it contacts the lock rod 22. As such, tension is placedon the lock rod 22 with the cylinder mechanism 90. This result is alocked tire press 10. In order to unlock the tire press 10, fluid isinjected on the release side 100 of the piston 96. Fluid is then removedfrom the squeeze side 98 of the piston 96. The lock ring 56 moves upwardand the first and second arms 58 can be opened. Upon release of the lockring 56, the tire press 10 is unlocked.

The guide rods 20 are offset at an angle in order to reduce the overallwidth of the tire press 28. It is advantageous to make the tire press 10as compact as possible so that it can be accommodated by existingfactory spaces. The orientation of the guide rods 20 and lock rods 22provide for such an advantage. Further, because of the presentinvention, the overall height of the tire press 10 is reduced, such thatpits may not be needed to accommodate the tire press 10.

With reference to FIG. 5, the tire loader assembly 83 is attached to thetop plate 12 and travels up and down with the movement of top plate 12.When the loader assembly 83 is moved in under top plate 12 top plate 12is lowered to place the tire over the bladder mechanism and into thebottom half of the mold. This method provides for a faster press cycletime, elimination of a separate lifting mechanism for the loader, andbetter precision placement of the tire onto the bladder mechanism.

The tire unloading mechanism 84 extends into the press to remove thecured tire by lifting it vertically over the bladder and thenhorizontally out the rear side of the press. The unloading mechanismthen retracts down vertically and deposits the cured tire on the takeaway conveyor or it can delay placement of the tire on the take awayconveyor and maintain the tire on the unloader arms during the next curecycle so that the cured tire cools in a level position and does notstrike any objects such as conveyor rolls while in a hot and sensitivecondition. When the unloader does retract fully down it passes throughand below the take away conveyor at the rear of the press. This allowsbetter access to the rear of the press for operation, mold change andmaintenance. It also provides for a more gentle and exact placement ofthe tire onto the take away conveyor.

The green tire holder 85 receives a green or uncured tire from a man orother mechanical delivery device. The holder then rotates horizontallyto a location centered under the loading mechanism 83. The holder thenlifts the tire vertically until the loading mechanism 83 can expand andattach to the tire. The holder then retracts down and rotates back tothe starting position for the next tire. This method reduces the motionsof the loader assembly, causes the loader to be more precise for thefinal placement of the tire into the mold, and provides more safety forthe operator than in the case where a loader drops to take a tire from afixed holder.

The preferred embodiments have been described, hereinabove. It will beapparent to those skilled in the art that the above methods mayincorporate changes and modifications without departing from the generalscope of this invention. It is intended to include all suchmodifications and alterations in so far as they come within the scope ofthe appended claims or the equivalents thereof.

1. An apparatus, comprising: an upper mold; a first top plate per uppermold, said top plate having the upper mold; a single bottom plate havinga bottom mold, said bottom mold having an upper surface defining a firstplane; three lock rods per top plate, each of said lock rods having afirst end and a second end, each of said lock rods having a surface;locking mechanism operatively connected to each of said lock rods,wherein said locking mechanism are operatively connected to said bottomplate; and, cylinder mechanisms operatively connected to said lockingmechanism, wherein said cylinder mechanisms are adapted to move saidlocking mechanism to said surface of said lock rods, said cylindermechanisms also adapted to place tension on said lock rods, wherein eachof said cylinder mechanisms is a hydraulic cylinder, said cylindermechanisms being supplied with hydraulic fluid from a common source,each of said cylinder mechanisms having a floating piston positionedtherein, said floating piston having a self-adjusting stroke; a loaderassembly operatively connected to said top plate; and wherein a lowersurface of said upper mold defines a second plane, said top plateadapted to adjust via the self-adjusting stroke of said floating pistonssuch that said second plane is parallel to said first plane such thatequal force is applied to each of said lock rods which results inuniform force being applied to said molds.
 2. The apparatus of claim 1,wherein said loader assembly is adapted to travel up and down with saidtop plate.
 3. The apparatus of claim 2, further comprising: a bladdermechanism; and, a mold having a bottom half, wherein said loaderassembly is positioned below said top plate such that the top plate canbe lowered to position the tire over said bladder mechanism and intosaid bottom half of said mold.
 4. An apparatus, comprising: an uppermold; a first top plate per upper mold, said top plate having the uppermold; a single bottom plate having a bottom mold, said bottom moldhaving an upper surface defining a first plane; three lock rods per topplate, each of said lock rods having a first end and a second end, eachof said lock rods having a surface; locking mechanism operativelyconnected to each of said lock rods, wherein said locking mechanism areoperatively connected to said bottom plate; and, cylinder mechanismsoperatively connected to said locking mechanism, wherein said cylindermechanisms are adapted to move said locking mechanism to said surface ofsaid lock rods, said cylinder mechanisms also adapted to place tensionon said lock rods, wherein each of said cylinder mechanisms is ahydraulic cylinder, said cylinder mechanisms being supplied withhydraulic fluid from a common source, each of said cylinder mechanismshaving a floating piston positioned therein, said floating piston havinga self-adjusting stroke; an unloading mechanism adapted to extend intosaid apparatus to remove an associated cured tire; and wherein a lowersurface of said upper mold defines a second plane, said top plateadapted to adjust via the self-adjusting stroke of said floating pistonssuch that said second plane is parallel to said first plane such thatequal force is applied to each of said lock rods which results inuniform force being applied to said molds.
 5. The apparatus of claim 4,wherein said unloading mechanism is adapted to move the cured tirevertically.
 6. The apparatus of claim 4, wherein said unloadingmechanism is adapted to move the cured tire horizontally.
 7. Theapparatus of claim 4, wherein said unloading mechanism is adapted tomove the cured tire vertically and horizontally.
 8. The apparatus ofclaim 7, wherein said unloading mechanism is adapted to move the curedtire vertically over a bladder mechanism and horizontally out of theapparatus.
 9. The apparatus of claim 4, wherein said unloading mechanismis adapted to retract vertically to deposit the cured tire on a takeaway mechanism.
 10. A tire press, comprising: an upper mold; a first topplate per upper mold, said top plate having the upper mold; a singlebottom plate having a bottom mold, said bottom mold having an uppersurface defining a first plane; three lock rods per top plate, each ofsaid lock rods having a first end and a second end, each of said lockrods having a surface; locking mechanism operatively connected to eachof said lock rods, wherein said locking mechanism are operativelyconnected to said bottom plate; and, cylinder mechanisms operativelyconnected to said locking mechanism, wherein said cylinder mechanismsare adapted to move said locking mechanism to said surface of said lockrods, said cylinder mechanisms also adapted to place tension on saidlock rods, wherein each of said cylinder mechanisms is a hydrauliccylinder, said cylinder mechanisms being supplied with hydraulic fluidfrom a common source, each of said cylinder mechanisms having a floatingpiston positioned therein, said floating piston having a self-adjustingstroke; a tire loader for a press, the tire loader having a loadingmechanism operatively connected to the press, wherein said tire loaderis adapted to move upwards and downwards relative to the press; andwherein a lower surface of said upper mold defines a second plane, saidtop plate adapted to adjust via the self-adjusting stroke of saidfloating pistons such that said second plane is parallel to said firstplane such that equal force is applied to each of said lock rods whichresults in uniform force being applied to said molds.
 11. The tire pressof claim 10, wherein said loading mechanism is operatively connected tosaid first top plate, said loading mechanism adapted to travel upwardand downwards with said first top plate.
 12. The tire press of claim 11,wherein said loading mechanism is adapted to move under said first topplate such that said first top plate can be lowered to position anassociated tire over a bladder mechanism and into said bottom mold. 13.The tire press of claim 11, further comprising a tire holder having aholding mechanism for a green tire, wherein said green tire holder isadapted to rotate horizontally to a predetermined position.
 14. The tirepress of claim 13, wherein said predetermined position is centered undersaid loading mechanism.
 15. The tire press of claim 12, wherein saidgreen tire holding mechanism is adapted to move the tire verticallyuntil the tire loading mechanism can operatively connect to the tire.16. The tire press of claim 15, wherein said green tire holder isadapted to retract downwards and rotate back to its starting position.